Solvent refining of hydrocarbon oil



Patented Apr. 16, 1935 UNITED STATES SOLVENT REFINING OF HYDROCARBON OIL Ernest F. Pevere, Beacon, N. Y., asslgnor to The Texas Company, New York, N. Y., a corporation of Delaware No Drawing. Application October 26, 1933, Serial No. 695,324

4 Claims.

This invention relates to refining hydrocarbon oil, and more particularly to refining mineral oil by solvent extraction.

The invention contemplates the treatment and b refining of mineral oil with a selective solvent CHz-QH3\ /O CHn-CH;

The foregoing solvent liquid is suitable for extracting undesired constituents from mineral oils, and particularly from lubricating oil fractions.

Lubricating oils, such as produced from Mid- Continent crude, are ordinarily composed of relatively paraffinic constituents, and also relatively non-paraflinic constituents,including naphthenic,

aromatic, and unsaturated hydrocarbon bodies. The solvent of my invention is adapted to extract these relatively non-parafiinic bodies from the oil for the production of lubricating oil fractions which are of relatively high paraflinic character,

' and therefore of relatively higher viscosity index than the untreated oil.

In the application of my invention to the treatment of mineral oils for the production of lubricating oil, one part of the oil is mixed with about two parts of solvent liquid, and this mixture is then subjected to agitation and heating in order to effect solution of the undesired constituents of the oil in the solvent. The extent to which the oil is soluble in the solvent will depend upon the nature of the oil as well as upon the condition of temperature and pressure employed. The conditions of temperature and pressure, as well as the ratio of solvent to oil, may be varied for the purpose of effecting the particular degree of extraction desired. The temperatures employed, for example, may range from about F. to 200 F. or thereabouts.

At temperatures above the boiling point of the solvent, i. e., above 150 F., it will, of course, be necessary to employ suflicient pressure to prevent vaporization.

Upon settling, the mixture separates into two layers, one of which comprises the constituents which it is desired to extract from the oil dissolved in the bulk of the solvent liquid, while the other layer comprises the undissolved and relatively paraiiinic oil in admixture with a relatively small amount of solvent.

The two layers are then separately withdrawn, and the solvent liquid recovered therefrom. If desired, the separated layers may be subjected to treatment with additional quantities of the solvent for the purpose of obtaining a series of fractions of diifering characteristics.

In some instances, it may be of advantage to carry out the extraction in the presence of a modifying solvent liquid, such as benzol or a light-petroleum naphtha, for the purpose of .facilitating the extraction and further controlling the extent thereof.

The lubricating oil distillate may be subjected to the foregoing extraction treatment, either before or after dewaxing, or subsequent to treatment with other solvents or chemicals.

The invention is not necessarily limited to the treatment of lubricating oil fractions, since the solvent may be adapted to the refining and puriflcation ,of various hydrocarbon or mineral oil fractions,'including naphtha, cracked naphtha, kerosene, etc., as well as residual or distillate fractions, or products derived from petroleum or other sources.

Obviously many modifications and variations of the invention, as hereinbefore set forth, may be made without departing from the spirit and scope thereof, and therefore only. such limitations should be imposed as are. indicated in the appended claims.

I claim:

1. The method of refining hydrocarbon oil containing relatively parafiinic and relatively nonparaflinic constituents, including naphthenic, aromatic, and unsaturated bodies, to-remove undesired relatively non-paraflinic constituents therefrom, which comprises extractively treating the oil with tetrahydrofurfurane whereby the undesired constituents are separated from the oil as an extract soluble in the solvent liquid.

2. The method of refining hydrocarbon oil con taining relatively paraflinic and relatively nonparaflinic constituents, including naphthenic, aromatic, and unsaturated bodies, to remove undesired relatively non-paraflinic constituents therefrom, which comprises extractively treating the oil with a solvent containing tetrahydrofurfurane whereby the undesired constituents are separated from the oil as an extract soluble in the solvent liquid.

3. The method of refining hydrocarbon oil containing relatively paraflinic and relatively non-paraflinic constituents, including naphthenic, aromatic, and unsaturated bodies, to remove undesired relatively non-paraffin ic constituents therefrom, which comprises extractively treating the oil with a solvent comprising a hydrogenated furan of the character of tetrahydrofurfurane whereby the undesired constituents are separated from the oil as an extract soluble in the solvent liquid.

4. The method of treating mineral lubricating oil containing relatively low and relatively high viscosity index constituents to separate the oil into fractions respectively rich in low and high viscosity index constituents comprising extracting the oil with tetrahydrofurfurane in the presence of a modifying solvent of the character of benzol whereby the mixture of solvent and oil separates into two liquid phases, one of which comprises a raflinate phase containing the relatively high viscosity index constituents, while the other comprises an extract phase containing the relatively low viscosity index constituents, separately removing the two phases, and removing the solvent therefrom.

ERNEST F. PEVERE. 

